Aura/GTK integration: Create a small stub library that can talk to GTK.

chrome/browser/ui/libgtk2ui/owned_widget_gtk2.cc

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/ui/libgtk2ui/owned_widget_gtk2.h"
+
+#include <gtk/gtk.h>
+
+#include "base/logging.h"
+
+namespace libgtk2ui {
+
+OwnedWidgetGtk::~OwnedWidgetGtk() {
+  Destroy();
+}
+
+void OwnedWidgetGtk::Own(GtkWidget* widget) {
+  if (!widget)
+    return;
+
+  DCHECK(!widget_);
+  // We want to make sure that Own() was called properly, right after the
+  // widget was created. There should be a floating reference.
+  DCHECK(g_object_is_floating(widget));
+
+  // Sink the floating reference, we should now own this reference.
+  g_object_ref_sink(widget);
+  widget_ = widget;
+}
+
+void OwnedWidgetGtk::Destroy() {
+  if (!widget_)
+    return;
+
+  GtkWidget* widget = widget_;
+  widget_ = NULL;
+  gtk_widget_destroy(widget);
+
+  DCHECK(!g_object_is_floating(widget));
+  // NOTE: Assumes some implementation details about glib internals.
+  DCHECK_EQ(G_OBJECT(widget)->ref_count, 1U);
+  g_object_unref(widget);
+}
+
+}  // namespace libgtk2ui